Thread count for kie server is hard coded for optaplanner extension

in OptaplannerKieServerExtension.java the minnimum thread count is hard-coded to be 2.
Also, threads will not be allocated until blocking queue is full.
For example if there are 6 requests on a 8 core box,
2 will be worked on, and 4 will wait in the blocking queue. New threads are not allocated until blocking queue is at capacity